Means of reinforcing vertical faces of road slabs



June 8, 1943. J. H. .xAcoBsoN` MEANS OF REINFORCING VERTICALFACES OFROAD SLABS 2 sheets-sheet 2 Filed April 2. 1942 Aww w Patented June 8,1943 MEANS or aEmFonoTNG VERTICAL'FACES oF Roan sms James H. Jacobson,Chicago. Ill.

Application April 2, 1942, Serial No. 437,308

(Cl. SML-18) 11 Claims.

The present invention is designed to aord reinforcement for the verticaledge faces of abutting concrete road slabs, and at the same time toprovide for the transfer of load stresses across the joint gap and todistribute' the vibrational stresses occasioned by rolling loads fromthe `im mediate point of impact into widely adjacent portions to theroad structure on opposite sides of the gap.

With these purposes in view, the structure is designed to extend in theform of hingedly con-- nected sections from side to side of a road ortramc lane, so that a continuous connection will be afforded throughoutin contradistinction to conventional types of road joints which areintroduced at spaced intervals without additional connection save thataii'orded by the concrete itself.

A further object of the invention is to so construct the appliance thatthe constituent sections may be of uniform shape and formed from platemetal stampings, requiring no additional fabri. cation, which are usedin cooperation with dowel bars of conventional type formed from metalrods which not only serve' to transfer load stresses I gap willbe-bridged or filled by some suitable form of joint seal, metallic orbrous, but the means provided for sealing the gap form no portionof thepresent invention and need not be described in detail. It will alsobeunderstood that inthe pouring of the concrete the joint bars will besupplemented by suitable forms for temporarily across the gap but alsoserve to connect the constituent sections and to transfer vibrationalstresses thereto for distribution throughout; the f structure.

Further objects and details will appear from the description of theinvention in conjunction with the accompanying drawings, wherein- Figure1 is a plan view of a portion of a roadway embodying the structure ofthe present invention and indicating in dotted lines the method ofdistributing vibrational stresses;

Fig. 2 is a plan view of a plurality of the joint bars interconnected bydowel bars;

Fig. 3 is a rear elevation of one of the joint bars; and

Fig. 4 isa sectional view taken in part on line 4--4 of Fig. 2, with theconcrete of the road slabs cut back to the line c-c.

The joint appliance as a whole comprises a plurality of facing jointbars I0 which have their ends overlapped, and with the barsstandingedgewise in staggered relation and alternately embedded withinthe opposed joint faces of the concrete slabs II on opposite sides ofthe joint gap. The arrangement is one in which each slab face willprovide separated portions which are faced by the joint bars on thesameside of the gap with intervening portions where the bare surface ofthe concrete face is exposed. That is to say, each portion of the gapwill be faced on one side only save at the points where the ends of thebars overlap one another. Y

As shown in Fig. 4, the joint bars are of overall height slightlygreater than one-half the depth oi the joint gap, and it will beunderstood that in the completed joint the upper portion of the conningthe wet concrete in those portions of the joint which are not faced' bythe joint bars. or otherwise confined, but due to the peculiarity of thedesign o'f the face plates of the two halves through which the dowel baris placed, it is possible and practical to use a board or other meansfor producing a denite resisting wall for the wet immature concretemixture before and during the hardening process.

The length or height of the units will be determined by the design oftheslab which they tend to join and hold in` alignment with the nextabutting slab of similar design. In an ordinary roadway or traffic lane,eight of the bars of uniform length, with their ends overlapped, will beemployed, with the understanding, however, that the main reinforcingstructure may be supplemented at its ends by shorter bars of specialshape or dimension to aiiord curve or gutter sections Which may berequired by local conditions.

Each of the bars is formed of a stiff metal plate congured to afford anelongated body portion I3 which near each end is provided' with anupstanding ear Il having formed therein an aperture I5 of a size toreceive a dowel bar when the ends of the joint bars are overlapped tobring the` apertures Ii into register.

Between the upstanding ears, the body of the bar along its upper edge isprovided with a pair of obliquely disposed backwardly' and upwardlysloping intermediate wings I6, which are bent to present their uppersloping faces in inwardly convergent relation to one another, and whichare deeply embedded within the concrete slab to which the bar isattached.

The wings are bent obliquely backwardly and upwardly along obliquebending lines I1 which converge toward the center, which arrangementpresents the sloping at faces of the wings in convergent relation toioneanother and with the broad surface exposure to resist vertical thrust,and being deeply embedded in the concrete they serve to firmly anchorthe center portion of the joint bar.

The intermediate wings I6 are supplemented by inner and outer end wings.I8 and I9 located on each side of the ears I4. which end wings are bentbackwardly along oblique inwardly convergent bending lines 2l! and 2|,which configuration of the end wings affords a, rm anchorage againstlongitudinal displacement of the bar in either direction and presentsthe extended faces of the wings to resist vertical thrust. Thus 'all ofthe wings in conjunction being deeply embedded effect a part of theconcrete slab itself and thus afford a definite support for the dowelbar, while the oblique disposition of all of the wings permits theconcrete to easily flow beneath the wings and become firmly and closelypacked su that the formation of gaps or pockets inthe concrete isavoided.

In order to provide for expansion and contraction, one end of each ofthe dowel bars is provided with a tubular cap or sheath 22 of the usualcharacter, which provides a, void or gap to permit free movement of theend of the dowel bar, and in order to prevent bonding oi' the concreteto the exposed portions of the dowel and adjacent the cap, it ispreferred to grease the same prior to the pouring of the concrete. Inpreparation for the pouring of the concrete, the joint bars are spacedapart from one another to afford a gap of the intended width, the barsbeing supplemented by temporary forms to exclude the concrete throughoutthe length and depth of the intended gap, after which the concrete ispoured, which embeds the joint bars in staggered relation on oppositesides of the gap, and with their inner sides exposed to afford on eachside an interrupted metallic facing which confronts the bare concrete onthe other side, after the joint has been completed and the temporaryform members removed, it being understood that a suitable filling offiber or other acceptable material will thereafter be provided toprevent the intrusion of foreign materials into the gap.

The overlapped ends of adjacent joint bars are supported upon a flatfoot 23 which is preferably a section of the plate which is stamped outof the stock in the formation of the wings and which is welded to one ofthe bar ends along the weld line 24,`wh.ich provides a, support toprevent toppling of the joint structure prior to the pouring of theconcrete.

In positioning the bars, the two ends are overlapped and the dowelsentered through the registering apertures, which affords a hingeconnection for the adjacent joint bars, and in view of the fact thateach dowel bar is entered through two overlapped bars, each of which isfirmly anchored into the slab with which it is associated, it will beseen that the dowel bars afford a degree of flexibility equal to theelasticity or plasticity of the concrete itself which unifies thestructure throughout.

With the joint bars thus embedded and having their ends connected by thedowel bars, a continuous hinged reinforcement will be provided from endto end of the gap and transversely of the roadway. i

In the distribution of stresses occasioned 'by a rolling load, as forinstance by the two laterally spaced wheels of a truck, the resistanceagainst vertical displacement of the slabs will be that afforded by thedowel bars, which in turn are supplemented by the support afforded bythe overlapped ends of the joining bars between dowels which are firmlyand deeply anchored into the faces of the road slabs. The more distantends of the joint bars are likewise supported by other of the dowelbars, so that the structure throughout is tied together in such a waythat every por- -tion of the structure wil1 cooperate and assist inresisting displacement, irrespective of the particular points whichreceive the full impact ni the wheels.

The vibrational stresses set up by repeated impact of a Wheel load whichnormally causes disintegration of the concrete at points immediatelysurrounding the dowel bar and at the face of the vertical plane areprevented from causing funneling, due to the fact that the aperturesthrough the vertical plates of the ends of adjoining bars are a. steelreinforcement which within itself is properly and firmly embedded intothe face of the vertical plane. Thus the stresses are distributed indiminishing degree and in undulatory or wavelike lines of progressionfrom the points of impact, and in diminishing height as indicated by thedotted lines in Fig. 1. It will also be noted that there is a radialdistribution of stresses through the ends of the anchoring wings andthrough the dowel bars, so that every portion of the structure coacts inresisting the effects of impact wheresoever applied.

In view of the fact that the joint bars are set in staggered relation onopposite sides of thejoint gap, and are anchored to the concretealternately on opposite sides, the vibrational stresses will flow backand forth across the gap in diminishing degree as indicated, and willtend to diminish out or become absorbed as they advance away from thepoints of impact. This damping out action is promoted by reason of thefact that the lines of vibration, traveling in opposite directions, willtend to neutralize or extinguish one another.

The hinging of the joint bars on the dowels also affords a limiteddegree of flexibility, which is highly desirable, while the entirestructure is tied together from end to end so that there is no break inthe continuity of the connections through which stresses applied at anyparticular point are distributed and absorbed. Each dowel bar thereforecontributes in varying degree in a cooperative action which extendsthrough the entire series.

The simplicity of the structure offers few problems of installation andis adaptable to the various cross sections desired by highway engineersin various States. The design is also one which simplifies the making ofadditions, such as in widening sections of curves. The resultantdiffusion of stresses across a number of dowel bars indicates thefeasibility of engagement of more than one dowel bar across the abuttingslabs and permits calculation of the transference of load from eachindividual axis point of the dowel bar in correlation one with theother.

Although the invention has been described with particular detail, itwill be understood that the shape and dimensions of the joint bars andthe location and arrangement of the anchoring wings may be variedwithout departing from the principles of the invention.

I claim: v

l. In road joint reinforcing means of the character described, aplurality of joint bars arranged in spaced staggered relation to oneanother and having their ends in overlapping relation, and a loadtransference member entered through the overlapped ends of the bars andbridging the spaced bars and forming a hinge connection therefor andprojecting outwardly in each direction from the bars and in position tohave the projecting ends entered through the opposed faces of road slabsand into the interior of the slabs.

2. In road joint reinforcing means of the character described, aplurality of joint bars arranged in spaced staggered relation to oneanother and having their ends in overlapping relation, and a loadtransference member entered through the overlapped ends of the bars andbridging the spaced bars and forming a hinge connectionl therefor andprojecting outwardly in each direction from the bars and in position tohave the projecting ends entered through the opposed faces of road slabsand into the interior of the slabs, each of the bars being provided withanchoring members extending backwardly from the bar and in position tobe 'embedded within the associated road slab.

' 3. In road joint reinforcing means 0f the character described,`aplurality of joint bars arranged in spaced staggered relation to oneanother and having their ends in overlapping relationl and a loadtransference member entered through the overlapping ends of the bars andbridging the spaced bars and forming a hinge connection therefor andprojecting outwardly in each direction from the bars and in position tohave the projecting ends entered through the opposed faces of road slabsand into the interior of the slabs. each of the bars being provided withbroadly surfaced anchoring wings extending backwardly and upwardly topresent their broad faces in oblique relation to the surface of the roadslabs.

l4. In road joint reinforcing means of the character described, aplurality of joint bars arranged in spaced staggered relation to oneanother and having their ends in overlapping relation, and a loadtransference member entered through the over-lapped ends of the barsandbridging the fs'ped"bars and forming a hinge connection therefor andprojecting outwardly in each direction from the barsv and in position tohave the projecting ends entered through the opposed faces of road slabsand into the interior of the slabs. each of the bars being provided withbroadly surfaced anchoring wings extending backwardly and upwardly fromthe upper edge of the bar and in obliquely convergent relation to oneanother to present their broad faces in oblique relation to the surfaceof the road slabs.

5. In road joint reinforcing means of the character described, aplurality of joint bars arranged in spaced staggered relation to oneanother and having their ends in overlapping relation, and a loadtransference member entered through the overlapped ends of the bars andbridging the spaced bars and forming a hinge connection therefor andprojecting outwardly in each direction from the bars and in position tohave the projecting ends entered through the opposed faces of road slabsand into the interior of the slabs, each of the bars being provided inits medial region with a pair of broad surfaced anchoring wingsextending backwardly and upwardly from the upper edge of the joint barand presenting their broad surfaces in oblique convergentrelation to oneanother, and each bar having at each end a pair of broad surfacedanchoring wings extending backwardly and upwardly from the upper edge ofthe bar. and presenting their broad surfaces in obliquely convergentrelation to one another.

6. In road joint reinforcing means of the character described, thecombination of a plurality of joint bars standing vertically edgewise instaggered relation on opposite sides of the intended joint gap and withtheir ends in spaced overlapping relation to one another, and a dowelbar entered through each pair of overlapping ends to afford a hingeconnection therewith and hav-- ing the ends of the dowel bars projectingbackwardly in position to be embedded within the road slabs on oppositesides of the intended joint, each of the joint bars having along itsupper edge a plurality of backwardly and upwardly extend ing anchoringwings adapted to be embedded within the associated road slab, the wingscomprising an intermediate pair located in the medial region of the barand extending in obliquely convergeht .relation to one another and alsocomprising two end pairs, the wings of each pair standing in obliquelyconvergent relation to one another and on opposite sides of theproximate dowel bar.

7. A road joint reinforcing bar formed of plate material, having at eachend an aperture adapted to receive a dowel bar and having a plurality ofanchoring wings struck backwardly from the bar and adapted for embedmcntwithin a road slab.

8. A road joint reinforcing bar of elongated formation and formed ofplate material, having at each end an upstanding ear provided with anaperture adapted to receive a dowel bar and having va plurality ofanchoring wings projecting from the upper edge of the bar and extendingbackwardly and upwardly therefrom and tilted to present their faces inconvergent relation to one another.

9. A road joint reinforcing bar formed of plate material, having anelongated body and having at each end an upstanding ear provided with anaperture adapted to receive a dowel bar and having formed on its upperedge an intermediate pair of baekwardly and upwardly extending anchoringwings tilted to present their' faces in convergent relation to oneanother and also having on opposite sides of each ear a pair of endwings extending backwardly and upwardly from the upper edge of the barand tilted to present their faces in convergent relation to one another.

10. In a road joint, in combination with a pair of opposed concreteslabs separated by a gap. a

road joint reinforcing structure comprising a plurality of joint barsalternately secured to the opposed slabs on opposite sides of the gapand with their ends standing in spaced overlapping relation, theoverlapped bars being provided with anchoring means extending backwardlyinto the associated road slab to provide reinforcement alternately onopposite sides of the gap, leaving the intermediate portions of eachslab unreinforced.

and spaced dowel bars entered through the overlapped ends of adjacentjoint bars, each dowel bar having its projecting ends entered into theroad slabs on opposite sides of the gap, the reinforcing structureextending continuously throughout the length of the joint gap andaffording a recurrently hinged reinforcement for the joint. A 11, Inroad joint reinforcing means of the char acter described, a plurality ofjoint bars having their ends'in contiguous relation to one another, anda load transference member entered through the contiguous ends ofadjacent bars to afford a hinge connection therefor and having .the endsof the load transference member projecting outwardly in each directionfrom the bars and in position to have the projecting ends entered'through the opposed faces of road slabs and into the interior of theslabs, each of the bars being provided with anchoring members extendingbackwardly from the bar and in a position to be embedded within theassociated road slab.

JAMES H. JAcoBsoN.

